<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .tip-bar {
      display: inline-flex;
      align-items: center;
      height: 30px;
      background-color: rgba(0,0,0,.4);
      border-radius: 16px;
    }
    img {
      width: 30px;
      height: 30px;
      border-radius: 50%;
      margin-right: 5px;
    }
    span {
      font-size: 13px;
      color: white;
      margin-right: 8px;
    }
  </style>
</head>
<body>
  
  
  <div class="tip-bar">
    <img src="https://bfs.biyao.com/group1/M01/A2/67/rBACVGA_iOuAYaTxAAAPbted3yE165.png" alt="">
    <span>183***138对这件商品感兴趣</span>
  </div>

  <script>
    // 1.从服务器拿到数据ajax/fetch请求
    let tipList = [
      {
        icon: 'https://bfs.biyao.com/group1/M01/A6/97/rBACYWBCHqyAFH5tAAANZXX5Eww646.png',
        title: 'coderwhy对这件商品感兴趣'
      },
      {
        icon: 'https://bfs.biyao.com/group1/M01/A2/67/rBACVGA_iOuAYaTxAAAPbted3yE165.png',
        title: '123***814对这件商品感兴趣'
      },
      {
        icon: 'https://bfs.biyao.com/group1/M00/7F/4E/rBACYV16HseAP-PnAAAW9bbVoKE463.png',
        title: '刘军对这件商品感兴趣'
      }
    ]

    // 2.动态的切换数据
    // 2.1.获取元素
    var tipBar = document.querySelector(".tip-bar")
    var imgEl = tipBar.querySelector("img")
    var spanEl = tipBar.querySelector("span")

    // 2.2.3s切换一次数据
    var currentIndex = 0 // 记录当前展示到的索引位置
    setInterval(function() {
      // 1> 根据索引获取item
      var tipItem = tipList[currentIndex]

      // 2> 给DOM设置内容
      imgEl.src = tipItem.icon
      spanEl.textContent = tipItem.title
      
      // 3> 重新计算索引
      currentIndex++
      if (currentIndex === tipList.length) {
        currentIndex = 0
      }
    }, 3000)

    // 随机
    // Math.floor(Math.random() * tipList.length)

  </script>

</body>
</html>